Python is developed by Guido Van Rossam in 1991. The name ‘Python’ is taken from the name of a popular fun show of Netherlands called “The Complete Monty Python’s Flying Circus” broadcast through BBC around 1969 to 1974, which the favourite show of Guido Van Rossam.

Python programming language can be said as a ‘Multi Paradigm Language’ since it has the features of Procedural programming like C, object oriented programming like C++, Java, scripting programming like Perl, JavaScript, modular programming like Modula. But most of the features of python are taken from C and ABC language.

Python is a language developed prior to java, but due to lack of demand of big data like other needs it was not popular till today.

Versions of Python:
3 basic versions
Python 1.0 introduced in Jan 1994
Python 2.0 introduced in October 2000
Python 3.0 introduced in Dec 2008

Python-3 not support Python-2
And Python -2 also not support Python -3

Since they are developed for different purposes

There will be no support for Python-2 after year 2020.

So, it is recommended to learn Python-3.

Language Basics
Keywords
pre-defined words those must be used in the same context for which they were created by language.

There are 30 keywords in Python.
eg: def, for, class, while, if, True etc

most of the python keywords are lower case words.

python is case sensitive language

IDENTIFIERS
Names assigned by the Programmer to his program elements like variable, function, class, array etc.

Program elements are the basic building blocks used to construct the program logic.

Rules to select identifier:
1. keywords should not be used
2. should not start with number, but number can be seen from 2nd letter
3. no space, symbol or special characters are allowed except underscore (_)
4. both lower and upper case letters are allowed

Invalid Identifiers:
def
1stNo
First Name
@Temp**1

Valid Identifiers:
No1
_1stNo
First_Name
Def
All Alphabets like a,b,c ..z